Function injectDefaultFilter

injectDefaultFilter(template: string, defaultText?: string): string
Ensures that each Liquid variable in the template string includes a default filter. If a variable already has a default filter, it is left unchanged. Otherwise, it appends a default filter with a placeholder message indicating the missing variable name.
Parameters
- template: string
  The Liquid template string to process.
- defaultText: string = 'missing variable'
  The default message prefix to use for missing variables.
Returns string
The updated template string with default filters injected where needed.
Example
```
const template = '{{ brand_name }}';
const output = injectDefaultFilter(template);
// output: '{{ brand_name | default: "[missing variable: brand_name]" }}'
```
Regex match details:
- match: The full Liquid tag including any filters, e.g. {{ brand_name | upcase }}
- expression: The inner expression inside the tag, e.g. brand_name | upcase
- Defined in src/liquid/index.ts:88